Sending and receiving faxes over VoIP is one of the technical difficulties that hasn't been completely solved yet. Although not as serious as emergency calls and power supplies during blackouts, a reliable method for sending faxes would help in the wider acceptance of VoIP. Sending and receiving faxes over VoIP is one of the technical difficulties that hasn't been completely solved yet. Although not as serious as emergency calls and power supplies during blackouts, a reliable method for sending faxes would help in the wider acceptance of VoIP.

The main difficulty is that faxes are a different kind of data than voice. Whereas voice data has to be delivered in real time in order to maintain a comfortable conversation, fax data can be delayed somewhat in order to guarantee that it is completely intact. It doesn't matter if some voice data is lost en route, but if this happens to fax data it creates an error in the fax transmission.

There have been many attempts to solve this problem